This application claims the priority of 199 35 238.0, 28 Jul. 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a vehicle audio system having an audio central unit used to connect one or more further audio components to one another via an associated first data bus, and having an interface for data communication between the first data bus and a second data bus of another type in the vehicle.
An example of a distributed system architecture is described in the publication H. Tajima et al., A Distributed Architecture Car Audio System, Transportation Electronics: Proceedings of the International Congress on Transportation Electronics, Warrendale, Pa., USA, SAE, October 1986, page 85. In addition, a vehicle audio system of the type mentioned above, shown schematically in FIG. 2, is known from vehicles of the applicant.
As FIG. 2 shows, this audio system contains an optical ring data bus 1, e.g. of the type commonly known by the abbreviation MOST, which is used to connect a plurality of audio components to one another. One of these forms an audio central unit 2 (also called a head unit) in which numerous functions are implemented, such as user interface control, bus master function, priority management, diagnosis function, radio and amplifier function etc. In addition, this conventional central unit 2 contains an interface for data communication between the audio data bus 1 and a second data bus 3 of the vehicle, e.g., a data bus commonly known by the abbreviation CAN-B, which connects various vehicle control units to one another. The audio central unit 2 uses the second data bus 3 to access a combination instrument 4, particularly for display purposes, and to access the rest of the “vehicle control unit environment” (e.g., to realize a diagnosis function and a multipurpose steering wheel function in which one or more audio functions can be controlled on the steering wheel by the system user). The audio central unit 2 controls the other available audio components (in the example shown a car telephone unit 5, a voice control system 6 and a sound system 7), which is an addition to the equipment of a standard system that increases convenience.
The overall range of tasks of the conventional audio central unit 2 is therefore very comprehensive and complex, with at least some of these functions being different according to specific vehicle type and/or country, for various types of vehicle and countries of use. Furthermore, the respective audio components are often supplied by various component manufacturers for different types of vehicle (including different series), and/or for different countries, which lowers the number of units produced for each individual variant, even, and specifically, regarding the conventional audio central unit 2. As a further consequence, a relatively large amount of testing needs to be involved for the respective audio system.
A further problem in the conventional system is the different loudspeaker system connection. In a standard layout, contact is made with loudspeakers directly at the central unit, whereas, in the case of a convenience-enhancing layout containing the sound system 7, the loudspeakers are connected there and the output stages of the central unit 2 are then redundant and remain unused. For future standard systems, the four output stages used today will probably no longer be adequate; for technical reasons, it is very difficult or impossible to increase the number of output stages in the central unit 2.
One object of the invention is to provide a vehicle audio system of the type mentioned above which can be used for different types of vehicles and different countries, with comparatively little complication.
This and other objects and advantages are achieved by the vehicle audio system according to the invention, which includes an audio gateway unit as a separate component from the audio central unit. The audio gateway component not only acts as an interface for data communication between the audio data bus and another data bus of a different type in the vehicle, but also has one or more further functions implemented in it. The latter functions are those which are standard for various types of vehicle and/or countries of use, or those which can be parameterized in the audio gateway unit according to specific vehicle type and/or country and which can thus be matched to the respective type of vehicle and the respective country of use.
In this way, the audio central unit can be designed to be unencumbered by these functions, thereby significantly reducing its complexity as compared with the conventional system described above and shown in FIG. 2. This reduction in functions to be managed by the audio central unit generally means that fewer variants of the audio central unit are necessary for the various types of vehicle and countries of use. By implementing a loudspeaker output stage function in the audio gateway unit together with a sound system function, the audio central unit can be designed without such an output stage, so that the output stage is prevented from possibly remaining unused. As far as functions which are standard in terms of their spanning vehicle types and/or countries are concerned, a standard design of the audio gateway unit can be used for all types of vehicle and countries of use. As far as the functions which can be parameterized according to specific vehicle type and/or country are concerned, the audio gateway unit can be matched, by appropriate parameterization and hence relatively easily, to the particular instance of vehicle type and to the instance of the country of use, without the need for a great diversity of variants.
In one embodiment of the invention, with claim 2, one or more of the “amplifier”, “tuner”, “bus master” and “warning tone management” functions are implemented in the audio gateway unit, so that the associated audio central unit does not need to contain the relevant functions.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.